Introducing Nova: Arbitrum AnyTrust Mainnet is open for Developers

Offchain Labs
Offchain Labs
Published in
6 min readJul 11, 2022


tl;dr. The Arbitrum AnyTrust technology is ready for primetime! We’re launching Arbitrum Nova, a new chain built on our AnyTrust technology and we will be opening it up with a commitment to a fair launch. Arbitrum Nova is live on mainnet and open for developers to deploy their apps ahead of the upcoming launch to end users. Apply for developer access here.

What’s that in the distance? Do you see that? It’s becoming brighter… our first AnyTrust chain is upon us.

Earlier this year we announced Arbitrum AnyTrust, our new technology optimized for ultra low-cost transactions with strong security guarantees. Since then we’ve been working diligently and have now deployed our first chain built on the AnyTrust technology, and we’ve given the chain a name too: Arbitrum Nova.

(Wait, is the name Arbitrum AnyTrust or Arbitrum Nova?! Great question! The name of the chain is Arbitrum Nova and it’s built using the AnyTrust technology. This is analogous to Arbitrum One, which is a chain built using the Arbitrum Rollup technology).

This is a big step forward for everyone in the Ethereum and Arbitrum communities. With Nova operational we now have two separate Arbitrum chains running live on mainnet that together can support just about every blockchain use case. Nova will be the solution of choice for gaming and social applications, whereas Arbitrum One will continue to be the home for DeFi and many NFT projects.

Fair Launch

Nova will be fairly launched giving all developers equal access to have their apps live and ready when the network opens to users. Developers can request access today, and we’ll be opening the doors to users in the very near future.

OK I want to build. Where do I sign up?

As for next steps, developers can request access by applying here, after which we’ll provision access and new projects can start deploying. Arbitrum Nova has a chain ID of: 0xa4ba (decimal: 42170). You can read our new AnyTrust docs here, as well as view the block explorer. We’ll be rolling out additional documentation and other relevant resources in the coming weeks. We’ll be opening up to users soon, but we will be waiting at least 2 weeks to give developers time to onboard while Nova is permission-only.

One additional callout here is for projects that are planning on deploying a custom token to Nova. When the chain opens to the public, users will be able to deposit their tokens using our general bridge interface. This could result in confusion for some projects who would otherwise invoke special functionality when their tokens are bridged (i.e. directly increasing supply on Nova, etc.). For these projects it might make sense to prevent token deposits until custom bridging functionality is added. So for developers who want to prevent deposits on our general bridge web interface, please let us know within the developer-only period — which you can do through this form. If you’re unsure about whether or not you need to build custom bridging functionality, this page should help in that decision.

Wat’s Next? Wen Nitro on Arbitrum One?

As mentioned, we’ll be giving developers at least two weeks to prepare and build on Nova before end users have access. Our next step will then be to open Arbitrum Nova up to everyone and our priority at that point will be ensuring chain stability and continual onboarding of new projects and fostering a robust ecosystem. We expect the public rollout of Nova to happen in the coming weeks, and we’ll also be sharing more details about the Data Availability committee and initial members before the Nova chain opens to users.

For our community of builders focused on Arbitrum One, we have even more exciting news coming in short order [alpha leak ahead]. We are very close to the Arbitrum Nitro migration and the last testing milestone before that happens on mainnet will be migrating the Arbitrum Rinkeby testnet to Nitro. We are days away from that and once that happens we’ll be full steam ahead. Additionally we are planning on standing up a new Nitro-based Arbitrum Goerli testnet to serve as the long-term Arbitrum testnet. We’ll be sharing more details around timing and what our developer community can expect with these changes in a follow-up post in the coming days.

How is Nova different from Arbitrum One?

Nova is our new chain built on top of our AnyTrust technology, whereas Arbitrum One is our existing chain built on our optimistic rollup technology. The key technical differentiator is that whereas Arbitrum One puts all transaction data on Ethereum all the time, Nova makes use of a data availability committee. In doing so, Nova achieves significant cost savings by first sending the data to the committee and only falls back to putting data on-chain if the committee fails to do its job. Nova is an entirely new chain with a different set of assumptions and is designed for gaming, social applications and more cost-sensitive use cases.

Nova is fully EVM compatible, and once Arbitrum One migrates to Nitro, pending the changes we mentioned earlier, developing on both chains will feel exactly the same. As for how the chains operate, there are two key differences.

Firstly, with Arbitrum Nova there is now a minimal trust assumption added to the process of handling transaction data — specifically an assumption that at least two committee members are honest. Instead of the sequencer batching and posting all calldata to L1, it shares data with the committee. The committee then signs Data Availability certificates (a.k.a. DACerts) for batches of transactions and only these certs are posted to L1, which results in much smaller storage requirements on the base layer. To actually keep data available, the committee runs Data Availability Servers which expose a REST API that allows data batches to be fetched by hash.

Secondly, and this is where developers will really feel it, as a result of the using the DAC, transactions on Nova will have significantly lower transaction fees compared to Arbitrum One. While Arbitrum One is already up to 97% cheaper than Ethereum for many transaction types, Nova will be significantly lower cost.

Nova is perfect for projects with cost-sensitive, high transaction volume expectations like games that frequently mint new items or currency or social projects with many different levers for on-chain interaction. As these types of projects scale, the need to drive transaction costs even lower becomes a top priority, and having a chain that supports that kind of growth is what we are looking to achieve with Nova. Of course, as Arbitrum Nova matures we’ll continue to add improvements that will drive costs down even further.

Looking ahead

If launching a new chain and opening it up for developers somehow wasn’t enough, have no fear — we have even more in store. As mentioned, the next big Nova milestone will be opening Nova up to all users and we will share more details later this month. We also plan to continue onboarding teams to Arbitrum One and helping projects prepare for Nitro, and as mentioned earlier we’ll share more details about the Arbitrum One Nitro migration process very soon 👀.

As always, we owe a huge thank you to our incredible community for building on Arbitrum One, and sharing your feedback, which helps us develop new products and features to help us on our mission to make Ethereum accessible to all. Please continue to engage in our Discord, and if you’re ready to take an even bigger step, please note that we are hiring! We wouldn’t be able to build out Nitro and Arbitrum Nova without the bandwidth to back it up, and with even more ambitious plans in the works, we’re always looking to add to the team. Feel free to peruse our job postings and apply if you’re interested in building the future of Ethereum.



Offchain Labs
Offchain Labs

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